A cheaper helpline for flooding victims has been opened for calls from the public after David Cameron overruled quango bosses who said it was "not appropriate" to publicise it during a flooding crisis.

The new Floodline number - 0345 9881188 - was released after complaints that callers were being charged up to 41p a minute to call the existing Environment Agency helpline on the premium rate number 0845 9881188, with the money going to a private firm.

The 0345 number had already been set up and was operational as part of a wider Whitehall move away from pricier 0845 numbers, but the EA said it was not promoting it "proactively" to avoid confusion.

But Downing Street said Mr Cameron wanted use of the premium number to be ended "as quickly as it possibly can be", and it was later revealed that the new helpline was open for calls.

The numbers will operate alongside one another for the coming period, providing identical information, to ensure that people with the old number are still able to get through.

A spokeswoman for the Environment Agency said: "The Environment Agency has never made any money by using an 0845 number. Most people pay nothing to call Floodline from a landline as 0845 numbers are free as part of their call packages. The cost of calls from mobiles is determined by the phone service provider.

"However we want to make sure the public do not pay over the odds to for information. An 0345 number is now running in parallel with the 0845 number as part of this transition, giving people an alternative.

"The full switch over to 0345 9881188 will take place as soon as possible. However, we have been in a heightened incident since early December and took the decision not to start to promote the new number as we did not want confuse the public and jeopardise public safety.

"We will work with Natural Resources Wales and the Scottish Environmental Protection Agency, who also use Floodline, to start wide-scale promotion of the new number as soon as possible."

The Agency said free flood warning information was available on its website, Twitter feed and Facebook page, as well as through the Floodline Warning Direct service via phone, text message and email and a FloodAlerts application on Facebook.

Mr Cameron said in a message on Twitter: "Calls to flooding helplines shouldn't be premium rate - I'm pleased the EA has introduced a cheaper UK-wide number: 0345 988 1188."

Telecommunications watchdog Ofcom has encouraged all public bodies to use 03 numbers, which are charged at the same rate as calls to 01 or 02 "geographical" numbers and must be included within "free call" bundles in phone packages. Calls to 03 numbers cost between 0p-10p per minute from landlines and 10p-40p from mobiles, though most mobile users will pay at the lower end of this range.

Environment Agency chairman Lord Smith said he had not visited the Somerset Levels since they were submerged and admitted "we probably have not done as much as we should have done" to dredge the area's rivers.

He told Sky News: "I haven't yet been, in the last four weeks, to the Somerset Levels but I have been to the Somerset Levels on three occasions in the course of the last year and will be going back there."

He acknowledged that dredging of the Tone and Parrett rivers would have to be "an element" of plans to manage the flood risk in future.

Asked if the Environment Agency had been wrong up until now he said: "We probably have not done as much as we should have done up to now and I regret that. But we have had very difficult choices to make, reducing budgets to cope with.

"What we now need to do is work together with others, because it is not something just for the Environment Agency, we need to work with others in order to address the issues for the future."

Further flooding is expected as high sea levels, strong winds and large waves combine to increase the risk in coastal regions.

Severe flood warnings are in force along the River Severn, while further heavy rainfall could see flooding for much of south-west and southern England.

The River Severn in Shropshire, Telford and Wrekin, Worcestershire and Gloucestershire, the Frome and Avon in Dorset, the River Thames and its tributaries in Oxfordshire, west Berkshire, Reading, Slough and Hampshire, and the Medway in Kent could all be affected.

Since Friday evening, more than 87,000 homes have been protected from flooding, with 74,000 properties sent a free flood warning. Around 220 homes have been flooded.

Flood schemes have defended more than 1.1 million homes and businesses and protected nearly 2,500 square kilometres of farmland across England since early December.

Paul Mustow, the Environment Agency's flood risk manager, said: "Our thoughts are with those who have been affected by flooding. Environment Agency teams are working around the clock to protect homes and communities, and over 87,000 homes were protected over the weekend alone.

"With the Met Office forecasting further heavy rainfall and gales this week, and high tides set to continue, the country should be prepared for further flooding.

"In the face of this severe weather we would urge people to sign up to receive free flood warnings, check their flood risk and keep up to date with the latest situation on the Environment Agency website and on social media using #floodaware."

Environment Secretary Owen Paterson, who was summoned to the Commons to respond to an urgent question from his Labour opposite number Maria Eagle, said the Government is spending an extra £100,000 a week to pump water from flood ravaged areas of the Somerset Levels.

Mr Paterson, who was also due to chair a meeting of the Government's emergency committee Cobra, said 21 properties remained flooded and 200 people were still cut off.